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An international, collaborative investigation is undertaken to evaluate the relative merits and limitations of various numerical methods and experimental measurement techniques, specifically for the analysis of flapping-wing propulsion. A finite aspect-ratio configuration is extensively investigated, both quantitatively and qualitatively, in a low-speed wind tunnel. Direct force measurements are made, as well as time-accurate and time-averaged laser Doppler velocimetry and unsteady flow visualization. The reduced frequency, mean angle of attack, aspect ratio and Reynolds number are varied in the experiments. The experiment is numerically simulated using flat-plate theory, two and three-dimensional panel codes, and two and three-dimensional Euler and Navier-Stokes solvers. The ability of each of the methods to capture important aspects of the flow physics are evaluated through comparisons with each other and the experimental data. Additionally, the comparisons indicate areas where further research is needed. The collaborative effort provides a survey of available capabilities and provides a fixed set of flapping-wing data for others to compare against.

The topic that was investigated was whether there is a lift and thrust
benefit to flapping an underwater, biologically inspired three dimensional foil
near the solid bottom surface (so that it was in ground effect). The ...

Recent interest in flapping-wing propulsion, in particular for hovering or low-speed flight of micro air vehicles, has led to a renewed interest in the measurement and prediction of unsteady, vortex-dominated flows. The ...